Study On Preparation Of Silicon Brass From Copper Alloy Waste Material And Its Microstructure And Properties

Although lead brass has very excellent machinability and low production cost, it will causes harm to human body and environment, it is inevitable trend to develop the substitute of lead brass. In this work, nonleaded silicon brass was fabricated by using scraps as raw materials, such as H65, QSn6.5-1, BZn18-26, which has accomplished the aim of low production cost and environment, the microstructure and properties of as-cast silicon brass was analysed by OM, XRD, SEM, EDS and so on, this paper study on the influence of silicon content to the microstructure and properties of silicon brass. Mainly conclusions as follows:(1) Nonleaded silicon brasses have been prepared by using the H65, QSn6.5-1and BZn18-26scraps as raw materials. The organizations of silicon brass is mainly composed of a and (3phase, and with the increase of Si content, the percentage of a phase decrease gradually, while the percentage of β phase increase gradually. The microstructure morphology of silicon brass(0.2%-’0.6%Si) is lath-shaped a phase and β phase which distribute in grain boundary and inside ofa phase; The microstructure morphology of silicon brass(0.8%Si) is equiaxed β grain and short lath-shaped a phase which distribute in (3grain boundary and inside; The microstructure morphology of silicon brass(1%Si) is mainly equiaxed β grain. The element of Si, Mg will form granular phase with other alloy element which are Cu5Si+β.(2) The fluidity of silicon brass is tested by linear-type graphite mould and star-type graphite mould respectively. The flowing length of silicon brass(378-453mm) in linear-type graphite mould are longer than that of lead brass(221mm), and the length increase gradually with the increase of Si content. In the star-type graphite mould, with the the increase of pouring temperature, The average flowing length of silicon brass(0.2%、0.4%、0.6%Si) increase gradually, while the the average flowing length of silicon brass(0.8%、1.0%Si) increase firstly and then decrease slightly; At the same pouring temperature, with the increase of Si content, the average flowing length of silicon brass increase firstly and then decrease slightly.(3) To measure the biggest deformation degree of silicon brass by the hot compress test at the different temperature. The test temperature and the silicon content are the mainly factors to the biggest deformation degree, when the temperature is600℃、650℃、700℃, with the increase of Si content, the biggest deformation degree of silicon brass increase gradually; when the temperature is750℃、800℃, the biggest deformation degree of silicon brass is increase firstly and then reduce when the silicon content is up to1%. When the Si content is fixed, with the increase of temperature, the biggest deformation degree of silicon brass increase firstly and then reduce.(4) The silicon brasses have been cutted at different cutting condition. With the increase of depth of cutting, chip morphology of silicon brass have not changed while the width of chips became bigger. It can be found that the chip morphology of silicon brass(0.2%、0.4%Si) is "C" when compared with the chips of lead brass, the cutting property is worse than lead brass which are70%; the chip morphology silicon brass(0.6%Si) is strip, the cutting property is a bit worse than lead brass; the chip morphology silicon brass(0.8%、1.0%Si) is particle, the cutting property is equivalent to lead brass. With the increase of revolving speed, the chip morphology of alloy become longer, with the increase of feed rate, the chip morphology of silicon brass become smaller.(5) The average dezincification layer depth and corrosion rate of silicon brass (0.2%Si) are154.35μm,21.667g/m2·h respectively, which reduce69and60percent when compare with HPb59-1lead brass (the average dezincification layer depth and corrosion rate are511.46μm,57.916g/m respectively), The average dezincification layer depth and corrosion rate of silicon brass (1.0%Si) are281.55μm,39.583g/m2·h respectively, which reduce45and31percent when compare with HPb59-1.